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1.  The Shigella Type Three Secretion System Effector OspG Directly and Specifically Binds to Host Ubiquitin for Activation 
PLoS ONE  2013;8(2):e57558.
The genus Shigella infects human gut epithelial cells to cause diarrhea and gastrointestinal disorders. Like many other Gram-negative bacterial pathogens, the virulence of Shigella spp. relies on a conserved type three secretion system that delivers a handful of effector proteins into host cells to manipulate various host cell physiology. However, many of the Shigella type III effectors remain functionally uncharacterized. Here we observe that OspG, one of the Shigella effectors, interacted with ubiquitin conjugates and poly-ubiquitin chains of either K48 or K63 linkage in eukaryotic host cells. Purified OspG protein formed a stable complex with ubiquitin but showed no interactions with other ubiquitin-like proteins. OspG binding to ubiquitin required the carboxyl terminal helical region in OspG and the canonical I44-centered hydrophobic surface in ubiquitin. OspG and OspG-homologous effectors, NleH1/2 from enteropathogenic E coli (EPEC), contain sub-domains I-VII of eukaryotic serine/threonine kinase. GST-tagged OspG and NleH1/2 could undergo autophosphorylation, the former of which was significantly stimulated by ubiquitin binding. Ubiquitin binding was also required for OspG functioning in attenuating host NF-κB signaling. Our data illustrate a new mechanism that bacterial pathogen like Shigella exploits ubiquitin binding to activate its secreted virulence effector for its functioning in host eukaryotic cells.
doi:10.1371/journal.pone.0057558
PMCID: PMC3585378  PMID: 23469023
2.  The Shape Trail Test: Application of a New Variant of the Trail Making Test 
PLoS ONE  2013;8(2):e57333.
Objective
The Trail making test (TMT) is culture-loaded because of reliance on the Latin alphabet, limiting its application in Eastern populations. The Shape Trail Test (STT) has been developed as a new variant. This study is to examine the applicability of the STT in a senile Chinese population and to evaluate its potential advantages and disadvantages.
Method
A total of 2470 participants were recruited, including 1151 cognitively normal control (NC), 898 amnestic mild cognitive impairment (aMCI), and 421 mild Alzheimer disease (AD) patients. Besides the STT, the Mini mental state examination and a comprehensive neuropsychological battery involving memory, language, attention, executive function and visuospatial ability were administered to all the participants. In a subgroup of 100 NC and 50 AD patients, both the STT and the Color Trail Test (CTT) were performed.
Results
In NC, the time consumed for Part A and B (STT-A and STT-B) significantly correlated with age and negatively correlated with education (p<0.01). STT-A and B significantly differed among the AD, aMCI and NC. The number that successfully connected within one minute in Part B (STT-B-1 min) correlated well with STT-B (r = 0.71, p<0.01) and distinguished well among NC, aMCI and AD. In the receiver operating characteristic curve analysis, the AUCs (area under the curve) for STT-A, STT-B, and STT-B-1min in identifying AD were 0.698, 0.694 and 0.709, respectively. The STT correlated with the CTT, but the time for completion was longer.
Conclusion
The TMT is a sensitive test of visual search and sequencing. The STT is a meaningful attempt to develop a “culture-fair” variant of the TMT in addition to the CTT.
doi:10.1371/journal.pone.0057333
PMCID: PMC3577727  PMID: 23437370
3.  Detection of SNPs in the Cathepsin D Gene and Their Association with Yolk Traits in Chickens 
PLoS ONE  2013;8(2):e56656.
CTSD (Cathepsin D) is a key enzyme in yolk formation, and it primarily affects egg yolk weight and egg weight. However, recent research has mostly focused on the genomic structure of the CTSD gene and the enzyme’s role in pathology, and less is known about the enzyme’s functions in chickens. In this paper, the correlations between CTSD polymorphisms and egg quality traits were analyzed in local Shandong chicken breeds. CTSD polymorphisms were investigated by PCR-SSCP (polymerase chain reaction single strand conformation polymorphism) and sequencing analysis. Two variants were found to be associated with egg quality traits. One variant (2614T>C), located in exon 3, was novel. Another variant (5274G>T), located in intron 4, was previously referred to as rs16469410. Overall, our results indicated that CTSD would be a useful candidate gene in selection programs for improving yolk traits.
doi:10.1371/journal.pone.0056656
PMCID: PMC3576367  PMID: 23431385
4.  Virus Host Protein Interaction Network Analysis Reveals That the HEV ORF3 Protein May Interrupt the Blood Coagulation Process 
PLoS ONE  2013;8(2):e56320.
Hepatitis E virus (HEV) is endemic worldwide and a major cause of acute liver disease in developing countries. However, the molecular mechanisms of liver pathology and clinical disease are not well understood for HEV infection. Open reading frame 3 (ORF3) of HEV encodes a small phosphoprotein, which is assumed to be involved in liver pathology and clinical disease. In this study, the interactions between the HEV ORF3 protein and human proteins were investigated using a stringent, high-throughput yeast two-hybrid (Y2H) analysis. Thirty two proteins were shown to interact with genotype 1 ORF3, 28 of which have not been reported previously. These novel interactions were evaluated by coimmunoprecipitation of protein complexes from transfected cells. We found also that the ORF3 proteins of genotype 4 and rabbit HEV interacted with all of the human proteins identified by the genotype 1 ORF3 protein. However, the putative ORF3 protein derived from avian HEV did not interact with the majority of these human proteins. The identified proteins were used to infer an overall interaction map linking the ORF3 protein with components of the host cellular networks. Analysis of this interaction map, based on functional annotation with the Gene Ontology features and KEGG pathways, revealed an enrichment of host proteins involved in complement coagulation, cellular iron ion homeostasis and oxidative stress. Additional canonical pathway analysis highlighted the enriched biological pathways relevant to blood coagulation and hemostasis. Consideration of the clinical manifestations of hepatitis E reported previously and the results of biological analysis from this study suggests that the ORF3 protein is likely to lead to an imbalance of coagulation and fibrinolysis by interacting with host proteins and triggering the corresponding pathological processes. These results suggest critical approaches to further study of the pathogenesis of the HEV ORF3 protein.
doi:10.1371/journal.pone.0056320
PMCID: PMC3571956  PMID: 23418552
5.  Human Chorionic Gonadotropin β Induces Migration and Invasion via Activating ERK1/2 and MMP-2 in Human Prostate Cancer DU145 Cells 
PLoS ONE  2013;8(2):e54592.
We previously demonstrated that human chorionic gonadotropin β (hCGβ) induced migration and invasion in human prostate cancer cells. However, the involved molecular mechanisms are unclear. Here, we established a stable prostate cancer cell line overexpressing hCGβ and tested hCGβ-triggered signaling pathways causing cell migration and invasion. ELISA showed that the hCGβ amount secreted into medium increased with culture time after the hCGβ-transfected cells were incubated for 3, 6, 9, 12 and 24 h. More, hCGβ standards promoted MAPK (ERK1/2) phosphorylation and increased MMP-2 expression and activity in both dose- and time-dependent manners in hCGβ non-transfected cells. In addition, hCGβ promoted ERK1/2 phosphorylation and increased MMP-2 expression and activity significantly in hCGβ transfected DU145 cells. Whereas ERK1/2 blocker PD98059 (25 µM) significantly downregulated phosphorylated ERK1/2 and MMP-2. Particularly, hCGβ promoted cell migration and invasion, yet the PD98059 diminished the hCGβ-induced cell motility under those conditions. These results indicated that hCGβ induced cell motility via promoting ERK1/2 phosphorylation and MMP-2 upregulation in human prostate cancer DU145 cells.
doi:10.1371/journal.pone.0054592
PMCID: PMC3570544  PMID: 23424616
6.  Preoperative administration of bevacizumab is safe for patients with colorectal liver metastases 
AIM: To assess the impact of preoperative neoadjuvant bevacizumab (Bev) on the outcome of patients undergoing resection for colorectal liver metastases (CLM).
METHODS: Eligible trials were identified from Medline, Embase, Ovid, and the Cochrane database. The data were analyzed with fixed-effects or random-effects models using Review Manager version 5.0.
RESULTS: Thirteen nonrandomized studies with a total of 1431 participants were suitable for meta-analysis. There was no difference in overall morbidity and severe complications between the Bev + group and Bev - group (43.3% vs 36.8%, P = 0.06; 17.1% vs 11.4%, P = 0.07, respectively). Bev-related complications including wound and thromboembolic/bleeding events were also similar in the Bev + and Bev - groups (14.4% vs 8.1%, P = 0.21; 4.1% vs 3.8%, P = 0.98, respectively). The incidence and severity of sinusoidal dilation were lower in patients treated with Bev than in patients treated without Bev (43.3% vs 63.7%, P < 0.001; 16.8% vs 46.5%, P < 0.00, respectively).
CONCLUSION: Bev can be safely administered before hepatic resection in patients with CLM, and has a protective effect against hepatic injury in patients treated with oxaliplatin chemotherapy.
doi:10.3748/wjg.v19.i5.761
PMCID: PMC3574604  PMID: 23431050
Colorectal cancer; Liver metastases; Bevacizumab; Postoperative complication; Sinusoidal dilatation
7.  Selective inhibitory effect of HPMA copolymer-cyclopamine conjugate on prostate cancer stem cells 
Biomaterials  2011;33(6):1863-1872.
Improved treatments for prostate cancer are in great need to overcome lethal recurrence and metastasis. Targeting the tumorigenic cancer stem cells (CSCs) with self-renewal and differentiation capacity appears to be a promising strategy. Blockade of the hedgehog (Hh) signaling pathway, an important pathway involved in stem cell self-renewal, by cyclopamine leads to long-term prostate cancer regression without recurrence, strongly suggesting the connection between Hh pathway and prostate CSCs. Here we designed a HPMA (N-(2-hydroxypropyl)methacrylamide)-based cyclopamine delivery system as a CSC-selective macromolecular therapeutics with improved drug solubility and decreased systemic toxicity. To this end, HPMA and N-methacryloylglycylphenylalanylleucylglycyl thiazolidine-2-thione were copolymerized using the RAFT (reversible addition-fragmentation chain transfer) process, followed by polymer-analogous attachment of cyclopamine. The selectivity of the conjugate toward CSCs was evaluated on RC-92a/hTERT cells, the human prostate cancer epithelial cells with human telomerase reverse transcriptase transduction. The use of RC-92a/hTERT cells as an in vitro CSC model was validated by stem cell marker expression and prostasphere culture. The bioactivity of cyclopamine was retained after conjugation to the polymer. Furthermore, HPMA polymer-conjugated cyclopamine showed anti-CSC efficacy on RC-92a/hTERT cells as evaluated by decreased stem cell marker expression and CSC viability.
doi:10.1016/j.biomaterials.2011.11.029
PMCID: PMC3242878  PMID: 22138033
8.  K-rasG12V transformation leads to mitochondrial dysfunction and a metabolic switch from oxidative phosphorylation to glycolysis 
Cell Research  2011;22(2):399-412.
Increased aerobic glycolysis and oxidative stress are important features of cancer cell metabolism, but the underlying biochemical and molecular mechanisms remain elusive. Using a tetracycline inducible model, we show that activation of K-rasG12V causes mitochondrial dysfunction, leading to decreased respiration, elevated glycolysis, and increased generation of reactive oxygen species. The K-RAS protein is associated with mitochondria, and induces a rapid suppression of respiratory chain complex-I and a decrease in mitochondrial transmembrane potential by affecting the cyclosporin-sensitive permeability transition pore. Furthermore, pre-induction of K-rasG12V expression in vitro to allow metabolic adaptation to high glycolytic metabolism enhances the ability of the transformed cells to form tumor in vivo. Our study suggests that induction of mitochondrial dysfunction is an important mechanism by which K-rasG12V causes metabolic changes and ROS stress in cancer cells, and promotes tumor development.
doi:10.1038/cr.2011.145
PMCID: PMC3257361  PMID: 21876558
K-ras; mitochondrial dysfunction; glycolysis
9.  K-rasG12V transformation leads to mitochondrial dysfunction and a metabolic switch from oxidative phosphorylation to glycolysis 
Cell Research  2011;22(2):399-412.
Increased aerobic glycolysis and oxidative stress are important features of cancer cell metabolism, but the underlying biochemical and molecular mechanisms remain elusive. Using a tetracycline inducible model, we show that activation of K-rasG12V causes mitochondrial dysfunction, leading to decreased respiration, elevated glycolysis, and increased generation of reactive oxygen species. The K-RAS protein is associated with mitochondria, and induces a rapid suppression of respiratory chain complex-I and a decrease in mitochondrial transmembrane potential by affecting the cyclosporin-sensitive permeability transition pore. Furthermore, pre-induction of K-rasG12V expression in vitro to allow metabolic adaptation to high glycolytic metabolism enhances the ability of the transformed cells to form tumor in vivo. Our study suggests that induction of mitochondrial dysfunction is an important mechanism by which K-rasG12V causes metabolic changes and ROS stress in cancer cells, and promotes tumor development.
doi:10.1038/cr.2011.145
PMCID: PMC3257361  PMID: 21876558
K-ras; mitochondrial dysfunction; glycolysis
10.  Dominance of the CD4+ T helper cell response during acute resolving hepatitis A virus infection 
The Journal of Experimental Medicine  2012;209(8):1481-1492.
CD4+ T cells play a dominant role in control of acute HAV infection in chimpanzees.
Hepatitis A virus (HAV) infection typically resolves within 4–7 wk but symptomatic relapse occurs in up to 20% of cases. Immune mechanisms that terminate acute HAV infection, and prevent a relapse of virus replication and liver disease, are unknown. Here, patterns of T cell immunity, virus replication, and hepatocellular injury were studied in two HAV-infected chimpanzees. HAV-specific CD8+ T cells were either not detected in the blood or failed to display effector function until after viremia and hepatitis began to subside. The function of CD8+ T cells improved slowly as the cells acquired a memory phenotype but was largely restricted to production of IFN-γ. In contrast, CD4+ T cells produced multiple cytokines when viremia first declined. Moreover, only CD4+ T cells responded during a transient resurgence of fecal HAV shedding. This helper response then contracted slowly over several months as HAV genomes were eliminated from liver. The findings indicate a dominant role for CD4+ T cells in the termination of HAV infection and, possibly, surveillance of an intrahepatic reservoir of HAV genomes that decays slowly. Rapid contraction or failure to sustain such a CD4+ T cell response after resolution of symptoms could increase the risk of relapsing hepatitis A.
doi:10.1084/jem.20111906
PMCID: PMC3409494  PMID: 22753925
11.  ZNF-Mediated Resistance to Imatinib Mesylate in Gastrointestinal Stromal Tumor 
PLoS ONE  2013;8(1):e54477.
Although imatinib mesylate (IM) has transformed the treatment of gastrointestinal stromal tumors (GIST), many patients experience primary/secondary drug resistance. In a previous study, we identified a gene signature, consisting mainly of Kruppel-associated box (KRAB) domain containing zinc finger (ZNF) transcriptional repressors that predict short-term response to IM. To determine if these genes have functional significance, a siRNA library targeting these genes was constructed and applied to GIST cells in vitro. These screens identified seventeen “IM sensitizing genes” in GIST cells (sensitization index (SI) <0.85 ratio of drug/vehicle) with a false discovery rate (FDR) <15%, including twelve ZNF genes, the majority of which are located within the HSA19p12–13.1 locus. These genes were shown to be highly specific to IM and another tyrosine kinase inhibitor (TKI), sunitinib, in GIST cells. In order to determine mechanistically how these ZNFs might be modulating response to IM, RNAi approaches were used to individually silence genes within the predictive signature in GIST cells and expression profiling was performed. Knockdown of the 14 IM-sensitizing genes (10 ZNFs) universally led to downregulation of six genes, including TGFb3, periostin, and NEDD9. These studies implicate a role of KRAB-ZNFs in modulating response to TKIs in GIST.
doi:10.1371/journal.pone.0054477
PMCID: PMC3556080  PMID: 23372733
12.  IKKi Deficiency Promotes Pressure Overload-Induced Cardiac Hypertrophy and Fibrosis 
PLoS ONE  2013;8(1):e53412.
The inducible IκB kinase (IKKi/IKKε) is a recently described serine-threonine IKK-related kinase. Previous studies have reported the role of IKKi in infectious diseases and cancer. However, its role in the cardiac response to pressure overload remains elusive. In this study, we investigated the effects of IKKi deficiency on the development of pathological cardiac hypertrophy using in vitro and in vivo models. First, we developed mouse models of pressure overload cardiac hypertrophy induced by pressure overload using aortic banding (AB). Four weeks after AB, cardiac function was then assessed through echocardiographic and hemodynamic measurements. Western blotting, real-time PCR and histological analyses were used to assess the pathological and molecular mechanisms. We observed that IKKi-deficient mice showed significantly enhanced cardiac hypertrophy, cardiac dysfunction, apoptosis and fibrosis compared with WT mice. Furthermore, we recently revealed that the IKKi-deficient mice spontaneously develop cardiac hypertrophy. Moreover, in vivo experiments showed that IKKi deficiency-induced cardiac hypertrophy was associated with the activation of the AKT and NF-κB signaling pathway in response to AB. In cultured cells, IKKi overexpression suppressed the activation of this pathway. In conclusion, we demonstrate that IKKi deficiency exacerbates cardiac hypertrophy by regulating the AKT and NF-κB signaling pathway.
doi:10.1371/journal.pone.0053412
PMCID: PMC3551922  PMID: 23349709
13.  Temperature Sensitivity of Soil Organic Carbon Mineralization along an Elevation Gradient in the Wuyi Mountains, China 
PLoS ONE  2013;8(1):e53914.
Soil organic carbon (SOC) actively participates in the global carbon (C) cycle. Despite much research, however, our understanding of the temperature sensitivity of soil organic carbon (SOC) mineralization is still very limited. To investigate the responses of SOC mineralization to temperature, we sampled surface soils (0–10 cm) from evergreen broad-leaf forest (EBF), coniferous forest (CF), sub-alpine dwarf forest (SDF), and alpine meadow (AM) along an elevational gradient in the Wuyi Mountains, China. The soil samples were incubated at 5, 15, 25, and 35°C with constant soil moisture for 360 days. The temperature sensitivity of SOC mineralization (Q10) was calculated by comparing the time needed to mineralize the same amount of C at any two adjacent incubation temperatures. Results showed that the rates of SOC mineralization and the cumulative SOC mineralized during the entire incubation significantly increased with increasing incubation temperatures across the four sites. With the increasing extent of SOC being mineralized (increasing incubation time), the Q10 values increased. Moreover, we found that both the elevational gradient and incubation temperature intervals significantly impacted Q10 values. Q10 values of the labile and recalcitrant organic C linearly increased with elevation. For the 5–15, 15–25, and 25–35°C intervals, surprisingly, the overall Q10 values for the labile C did not decrease as the recalcitrant C did. Generally, our results suggest that subtropical forest soils may release more carbon than expected in a warmer climate.
doi:10.1371/journal.pone.0053914
PMCID: PMC3544745  PMID: 23342038
14.  3,3′-Diindolylmethane Protects against Cardiac Hypertrophy via 5′-Adenosine Monophosphate-Activated Protein Kinase-α2 
PLoS ONE  2013;8(1):e53427.
Purpose
3,3′-Diindolylmethane (DIM) is a natural component of cruciferous plants. It has strong antioxidant and anti-angiogenic effects and promotes the apoptosis of a variety of tumor cells. However, little is known about the critical role of DIM on cardiac hypertrophy. In the present study, we investigated the effects of DIM on cardiac hypertrophy.
Methods
Multiple molecular techniques such as Western blot analysis, real-time PCR to determine RNA expression levels of hypertrophic, fibrotic and oxidative stress markers, and histological analysis including H&E for histopathology, PSR for collagen deposition, WGA for myocyte cross-sectional area, and immunohistochemical staining for protein expression were used.
Results
In pre-treatment and reverse experiments, C57/BL6 mouse chow containing 0.05% DIM (dose 100 mg/kg/d DIM) was administered one week prior to surgery or one week after surgery, respectively, and continued for 8 weeks after surgery. In both experiments, DIM reduced to cardiac hypertrophy and fibrosis induced by aortic banding through the activation of 5′-adenosine monophosphate-activated protein kinase-α2 (AMPKα2) and inhibition of mammalian target of the rapamycin (mTOR) signaling pathway. Furthermore, DIM protected against cardiac oxidative stress by regulating expression of estrogen-related receptor-alpha (ERRα) and NRF2 etc. The cardioprotective effects of DIM were ablated in mice lacking functional AMPKα2.
Conclusion
DIM significantly improves left ventricular function via the activation of AMPKα2 in a murine model of cardiac hypertrophy.
doi:10.1371/journal.pone.0053427
PMCID: PMC3541184  PMID: 23326427
15.  Opiate addiction and cocaine addiction: underlying molecular neurobiology and genetics 
The Journal of Clinical Investigation  2012;122(10):3387-3393.
Addictive diseases, including addiction to heroin, prescription opioids, or cocaine, pose massive personal and public health costs. Addictions are chronic relapsing diseases of the brain caused by drug-induced direct effects and persisting neuroadaptations at the epigenetic, mRNA, neuropeptide, neurotransmitter, or protein levels. These neuroadaptations, which can be specific to drug type, and their resultant behaviors are modified by various internal and external environmental factors, including stress responsivity, addict mindset, and social setting. Specific gene variants, including variants encoding pharmacological target proteins or genes mediating neuroadaptations, also modify vulnerability at particular stages of addiction. Greater understanding of these interacting factors through laboratory-based and translational studies have the potential to optimize early interventions for the therapy of chronic addictive diseases and to reduce the burden of relapse. Here, we review the molecular neurobiology and genetics of opiate addiction, including heroin and prescription opioids, and cocaine addiction.
doi:10.1172/JCI60390
PMCID: PMC3534165  PMID: 23023708
16.  In ovo serial skeletal muscle diffusion tractography of the developing chick embryo using DTI: feasibility and correlation with histology 
Background
Magnetic resonance imaging is a noninvasive method of evaluating embryonic development. Diffusion tensor imaging (DTI), based on the directional diffusivity of water molecules, is an established method of evaluating tissue structure. Yet embryonic motion degrades the in vivo acquisition of long-duration DTI. We used a dual-cooling technique to avoid motion artifact and aimed to investigate whether DTI can be used to monitor chick embryonic skeletal muscle development in ovo, and to investigate the correlation between quantitative DTI parameters fractional anisotropy (FA) and fiber length and quantitative histologic parameters fiber area percentage (FiberArea%) and limb length.
Results
From 84 normally developing chick embryos, 5 were randomly chosen each day from incubation days 5 to 18 and scanned using 3.0 Tesla magnetic resonance imaging. A dual-cooling technique is used before and during imaging. Eggs were cracked for making histological specimen after imaging. 3 eggs were serially imaged from days 5 to 18. We show that skeletal muscle fibers can be tracked in hind limb in DTI beginning with incubation day 8. Our data shows a good positive correlation between quantitative DTI and histologic parameters (FA vs FiberArea%: r= 0.943, p<0.0001; Fiber_length vs Limb_length: r=0.974, p<0.0001). The result of tracked fibers in DTI during incubation corresponds to the development of chick embryonic skeletal muscle as reported in the literature.
Conclusion
Diffusion tensor imaging can provide a noninvasive means of evaluating skeletal muscle development in ovo.
doi:10.1186/1471-213X-12-38
PMCID: PMC3574849  PMID: 23268571
Magnetic resonance imaging; Diffusion tensor imaging; Skeletal muscle; Chick embryo
17.  Strand-specific RNA-seq reveals widespread occurrence of novel cis-natural antisense transcripts in rice 
BMC Genomics  2012;13:721.
Background
Cis-natural antisense transcripts (cis-NATs) are RNAs transcribed from the antisense strand of a gene locus, and are complementary to the RNA transcribed from the sense strand. Common techniques including microarray approach and analysis of transcriptome databases are the major ways to globally identify cis-NATs in various eukaryotic organisms. Genome-wide in silico analysis has identified a large number of cis-NATs that may generate endogenous short interfering RNAs (nat-siRNAs), which participate in important biogenesis mechanisms for transcriptional and post-transcriptional regulation in rice. However, the transcriptomes are yet to be deeply sequenced to comprehensively investigate cis-NATs.
Results
We applied high-throughput strand-specific complementary DNA sequencing technology (ssRNA-seq) to deeply sequence mRNA for assessing sense and antisense transcripts that were derived under salt, drought and cold stresses, and normal conditions, in the model plant rice (Oryza sativa). Combined with RAP-DB genome annotation (the Rice Annotation Project Database build-5 data set), 76,013 transcripts corresponding to 45,844 unique gene loci were assembled, in which 4873 gene loci were newly identified. Of 3819 putative rice cis-NATs, 2292 were detected as expressed and giving rise to small RNAs from their overlapping regions through integrated analysis of ssRNA-seq data and small RNA data. Among them, 503 cis-NATs seemed to be associated with specific conditions. The deep sequence data from isolated epidermal cells of rice seedlings further showed that 54.0% of cis-NATs were expressed simultaneously in a population of homogenous cells. Nearly 9.7% of rice transcripts were involved in one-to-one or many-to-many cis-NATs formation. Furthermore, only 17.4-34.7% of 223 many-to-many cis-NAT groups were all expressed and generated nat-siRNAs, indicating that only some cis-NAT groups may be involved in complex regulatory networks.
Conclusions
Our study profiles an abundance of cis-NATs and nat-siRNAs in rice. These data are valuable for gaining insight into the complex function of the rice transcriptome.
doi:10.1186/1471-2164-13-721
PMCID: PMC3549290  PMID: 23259405
Oryza sativa; Cis-NATs; Nat-siRNAs; SsRNA-seq; Transcriptome
18.  Identifying putative breast cancer-associated long intergenic non-coding RNA loci by high density SNP array analysis 
Frontiers in Genetics  2012;3:299.
Recent high-throughput transcript discoveries have yielded a growing recognition of long intergenic non-coding RNAs (lincRNAs), a class of arbitrarily defined transcripts (>200 nt) that are primarily produced from the intergenic space. lincRNAs have been increasingly acknowledged for their expressional dynamics and likely functional associations with cancers. However, differential gene dosage of lincRNA genes between cancer genomes is less studied. By using the high-density Human Omni5-Quad BeadChips (Illumina), we investigated genomic copy number aberrations in a set of seven tumor-normal paired primary human mammary epithelial cells (HMECs) established from patients with invasive ductal carcinoma. This Beadchip platform includes a total of 2,435,915 SNP loci dispersed at an average interval of ~700 nt throughout the intergenic region of the human genome. We mapped annotated or putative lincRNA genes to a subset of 332,539 SNP loci, which were included in our analysis for lincRNA-associated copy number variations (CNV). We have identified 122 lincRNAs, which were affected by somatic CNV with overlapped aberrations ranging from 0.14% to 100% in length. lincRNA-associated aberrations were detected predominantly with copy number losses and preferential clustering to the ends of chromosomes. Interestingly, lincRNA genes appear to be less susceptible to CNV in comparison to both protein-coding and intergenic regions (CNV affected segments in percentage: 1.8%, 37.5%, and 60.6%, respectively). In summary, our study established a novel approach utilizing high-resolution SNP array to identify lincRNA candidates, which could functionally link to tumorigenesis, and provide new strategies for the diagnosis and treatment of breast cancer.
doi:10.3389/fgene.2012.00299
PMCID: PMC3528021  PMID: 23267367
long intergenic non-coding RNA (lincRNA); copy number variation (CNV); SNP array; breast cancer
19.  Synergistic Role between p53 and JWA: Prognostic and Predictive Biomarkers in Gastric Cancer 
PLoS ONE  2012;7(12):e52348.
Expression of p53 appears to be correlated to prognosis in patients with malignancy, but its role in gastric carcinoma has remained controversial. Recently we reported that JWA, an ADP-ribosylation-like factor 6 interacting protein 5 (ARL6ip5), was both prognostic for overall survival and predictive for platinum-based treatment of gastric cancer. In this study, we aimed to investigate p53 expression as a prognostic and predictive marker in resectable gastric cancer, alone and in combination with JWA. Expression of p53 was examined in three large patient cohorts (total n = 1155) of gastric cancer. High expression of p53 was significantly correlated with unfavorable clinicopathologic parameters and decreased overall patient survival. Furthermore, patients with high p53 expression in tumors acquired remarkable survival benefit from adjuvant first-line platinum-based-chemotherapy. The synergy between p53 and JWA in predicting patient outcome was demonstrated, while no significantly elevated predictive value concerning chemotherapy was observed. Thus, p53 expression is a potent prognostic and predictive factor for resectable gastric cancer with adjuvant platinum-based chemotherapy. A combined effect of p53 with JWA as efficient prognostic indicators was found for the first time.
doi:10.1371/journal.pone.0052348
PMCID: PMC3528747  PMID: 23285001
20.  Expanding the Horizon of the Thymine Isostere Biochemistry: Unique Cyclobutane Dimers Formed via Photoreaction between a Thymine and a Toluene Residue in the Dinucleotide Framework 
Substituted toluenyl groups are considered as close isosteres of the thymine residue. They can be recognized by DNA polymerases as if they were thymine. These toluene derivatives are generally inert toward radical additions, including the [2+2] photo-cycloadditions, due to the stable structure of the aromatic ring and are usually used as solvents for radical reactions. Surprisingly, after incorporating toluene into the dinucleotide framework, we found that the UV excited thymine residue readily dimerizes with the toluenyl moiety through a [2+2] photo-addition reaction. Furthermore, the reaction site on the toluenyl moiety is not the C5=C6 bond, as commonly observed in cyclobutane pyrimidine dimers, but the C4=C5 or C3=C4 instead. Such a reaction pattern suggests that in the stacked structure, it is one of these bonds, not the C5=C6, that is close to the thymine C5=C6 bond. A similar structural feature is found in DNA duplex with a thymine replaced by a 2,4-difluorotoluene. Our results argue that although the substituted toluenyl moieties closely mimic the size and shape of the thymine residue, their more hydrophobic nature determines that they stack on DNA bases differently from the natural thymine residue and likely cause local conformational changes in duplex DNA.
doi:10.1002/chem.201200816
PMCID: PMC3374913  PMID: 22588824
cyclobutane pyrimidine dimers; DNA; photochemistry; stereochemistry; thymine
21.  Outcomes of Sustained-Release Formulation of Valproate and Topiramate Monotherapy in Patients with Epilepsy: A Multi-Centre, Cohort Study 
PLoS ONE  2012;7(12):e47982.
Background
New-generation antiepileptic drugs (AEDs) tend to replace traditional AEDs as the first-line choice for epilepsy. However, whether this change results in better outcome, especially in China, remains unknown.
Methodology/Principal Findings
Two broad spectrum AEDs, the traditional drug of sustained-release formulation of valproate (SRVPA) and the new-generation drug of topiramate, were compared in patients with epilepsy as monotherapy in this multi-centre, observational cohort study from 2000 to 2011. The primary outcome was time to treatment failure. The secondary outcomes included time to first seizure, time to 12-month remission, and time to 24-month remission. Drug tolerability was assessed. Cox proportional hazard models (95% confidence interval [CI]) were used to analyse the relative risks expressed as hazard ratios (HR).
Of the 1008 recruited patients, 519 received SRVPA and 489 received topiramate. SRVPA was better than topiramate (28.3% vs. 41.5%; HR = 0.62, [95% CI 0.49–0.77]; p<0.0001) in primary outcome, and in time to first seizure (56.1% vs. 69.3%; HR = 0.73, [95% CI 0.62–0.86]; p = 0.0002). No significant difference was observed between two groups in time to 12-month remission (52.6% vs. 42.5%; HR = 1.01, [95% CI 0.84–1.23]; p = 0.88) and time to 24-month remission (34.7% vs. 25.2%; HR = 1.11, [95% CI 0.88–1.42]; p = 0.38). 36 patients (6.9%) in SRVPA group and 37 patients (7.6%) in topiramate group presented treatment failure associated with intolerable adverse events, there was no significant difference between the two groups (p = 0.70).
Conclusions
The SRVPA is more suitable than topiramate for Chinese epileptic patients, and our results support the viewpoint that traditional AEDs should be the first-line choice for epilepsy rather than new-generation AEDs.
doi:10.1371/journal.pone.0047982
PMCID: PMC3519782  PMID: 23239963
22.  Short-Term Delayed Recall of Auditory Verbal Learning Test Is Equivalent to Long-Term Delayed Recall for Identifying Amnestic Mild Cognitive Impairment 
PLoS ONE  2012;7(12):e51157.
Delayed recall of words in a verbal learning test is a sensitive measure for the diagnosis of amnestic mild cognitive impairment (aMCI) and early Alzheimer’s disease (AD). The relative validity of different retention intervals of delayed recall has not been well characterized. Using the Auditory Verbal Learning Test–Huashan version, we compared the differentiating value of short-term delayed recall (AVL-SR, that is, a 3- to 5-minute delay time) and long-term delayed recall (AVL-LR, that is, a 20-minute delay time) in distinguishing patients with aMCI (n = 897) and mild AD (n = 530) from the healthy elderly (n = 1215). In patients with aMCI, the correlation between AVL-SR and AVL-LR was very high (r = 0.94), and the difference between the two indicators was less than 0.5 points. There was no difference between AVL-SR and AVL-LR in the frequency of zero scores. In the receiver operating characteristic curves analysis, although the area under the curve (AUC) of AVL-SR and AVL-LR for diagnosing aMCI was significantly different, the cut-off scores of the two indicators were identical. In the subgroup of ages 80 to 89, the AUC of the two indicators showed no significant difference. Therefore, we concluded that AVL-SR could substitute for AVL-LR in identifying aMCI, especially for the oldest patients.
doi:10.1371/journal.pone.0051157
PMCID: PMC3517417  PMID: 23236445
23.  A Loss-of-Function Mutation in the PAS Kinase Rim15p Is Related to Defective Quiescence Entry and High Fermentation Rates of Saccharomyces cerevisiae Sake Yeast Strains 
Applied and Environmental Microbiology  2012;78(11):4008-4016.
Sake yeast cells have defective entry into the quiescent state, allowing them to sustain high fermentation rates. To reveal the underlying mechanism, we investigated the PAS kinase Rim15p, which orchestrates initiation of the quiescence program in Saccharomyces cerevisiae. We found that Rim15p is truncated at the carboxyl terminus in modern sake yeast strains as a result of a frameshift mutation. Introduction of this mutation or deletion of the full-length RIM15 gene in a laboratory strain led to a defective stress response, decreased synthesis of the storage carbohydrates trehalose and glycogen, and impaired G1 arrest, which together closely resemble the characteristic phenotypes of sake yeast. Notably, expression of a functional RIM15 gene in a modern sake strain suppressed all of these phenotypes, demonstrating that dysfunction of Rim15p prevents sake yeast cells from entering quiescence. Moreover, loss of Rim15p or its downstream targets Igo1p and Igo2p remarkably improved the fermentation rate in a laboratory strain. This finding verified that Rim15p-mediated entry into quiescence plays pivotal roles in the inhibition of ethanol fermentation. Taken together, our results suggest that the loss-of-function mutation in the RIM15 gene may be the key genetic determinant of the increased ethanol production rates in modern sake yeast strains.
doi:10.1128/AEM.00165-12
PMCID: PMC3346387  PMID: 22447585
24.  Acute Ethanol Exposure Increases the Susceptibility of the Donor Hearts to Ischemia/Reperfusion Injury after Transplantation in Rats 
PLoS ONE  2012;7(11):e49237.
Background
Many donor organs come from youths involved in alcohol-related accidental death. The use of cardiac allografts for transplantation from donors after acute poisoning is still under discussion while acute ethanol intoxication is associated with myocardial functional and morphological changes. The aims of this work were 1) to evaluate in rats the time-course cardiac effects of acute ethanol-exposure and 2) to explore how its abuse by donors might affect recipients in cardiac pump function after transplantation.
Methods
Rats received saline or ethanol (3.45 g/kg, ip). We evaluated both the mechanical and electrical aspects of cardiac function 1 h, 6 h or 24 h after injection. Plasma cardiac troponin-T and glucose-levels were measured and histological examination of the myocardium was performed. In addition, heart transplantation was performed, in which donors received ethanol 6 h or 24 h prior to explantation. Graft function was measured 1 h or 24 h after transplantation. Myocardial TBARS-concentration was measured; mRNA and protein expression was assessed by quantitative real-time PCR and Western blot, respectively.
Results
Ethanol administration resulted in decreased load-dependent (−34±9%) and load-independent (−33±12%) contractility parameters, LV end-diastolic pressure and elevated blood glucose levels at 1 h, which were reversed to the level of controls after 6 h and 24 h. In contrast to systolic dysfunction, active relaxation and passive stiffness are slowly recovered or sustained during 24 h. Moreover, troponin-T-levels were increased at 1 h, 6 h and 24 h after ethanol injection. ST-segment elevation (+47±10%), elongated QT-interval (+38±4%), enlarged cardiomyocyte, DNA-strand breaks, increased both mRNA and protein levels of superoxide dismutase-1, glutathione peroxydase-4, cytochrome-c-oxidase and metalloproteinase-9 were observed 24 h following ethanol-exposure. After heart transplantation, decreased myocardial contractility and relaxation, oxidative stress and altered protein expression were observed.
Conclusions
These results demonstrate acute alcohol abuse increases the susceptibility of donor hearts to ischemia/reperfusion in a rat heart transplant model even though the global contractile function recovers 6 h after ethanol-administration.
doi:10.1371/journal.pone.0049237
PMCID: PMC3498334  PMID: 23155471
25.  Identifying breast cancer risk loci by global differential allele-specific expression (DASE) analysis in mammary epithelial transcriptome 
BMC Genomics  2012;13:570.
Background
The significant mortality associated with breast cancer (BCa) suggests a need to improve current research strategies to identify new genes that predispose women to breast cancer. Differential allele-specific expression (DASE) has been shown to contribute to phenotypic variables in humans and recently to the pathogenesis of cancer. We previously reported that nonsense-mediated mRNA decay (NMD) could lead to DASE of BRCA1/2, which is associated with elevated susceptibility to breast cancer. In addition to truncation mutations, multiple genetic and epigenetic factors can contribute to DASE, and we propose that DASE is a functional index for cis-acting regulatory variants and pathogenic mutations, and that global analysis of DASE in breast cancer precursor tissues can be used to identify novel causative alleles for breast cancer susceptibility.
Results
To test our hypothesis, we employed the Illumina® Omni1-Quad BeadChip in paired genomic DNA (gDNA) and double-stranded cDNA (ds-cDNA) samples prepared from eight BCa patient-derived normal mammary epithelial lines (HMEC). We filtered original array data according to heterozygous genotype calls and calculated DASE values using the Log ratio of cDNA allele intensity, which was normalized to the corresponding gDNA. We developed two statistical methods, SNP- and gene-based approaches, which allowed us to identify a list of 60 candidate DASE loci (DASE ≥ 2.00, P ≤ 0.01, FDR ≤ 0.05) by both methods. Ingenuity Pathway Analysis of DASE loci revealed one major breast cancer-relevant interaction network, which includes two known cancer causative genes, ZNF331 (DASE = 2.31, P = 0.0018, FDR = 0.040) and USP6 (DASE = 4.80, P = 0.0013, FDR = 0.013), and a breast cancer causative gene, DMBT1 (DASE=2.03, P = 0.0017, FDR = 0.014). Sequence analysis of a 5′ RACE product of DMBT1 demonstrated that rs2981745, a putative breast cancer risk locus, appears to be one of the causal variants leading to DASE in DMBT1.
Conclusions
Our study demonstrated for the first time that global DASE analysis is a powerful new approach to identify breast cancer risk allele(s).
doi:10.1186/1471-2164-13-570
PMCID: PMC3532379  PMID: 23107584
Differential allele-specific expression; Breast cancer susceptibility; SNP array; DMBT1

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